Hi ALL!
Since long time I digested all knowledge I could find along TB6600 driver. I own a good German ISEL mill (mechanic only) (workig area ca. 20"x20") with NEMA23 motors. After I burnt a 4 channel Chineese board I took the chance to deep dive into the matter. Unfortunately I find in most posts complaints and seaching for help or those cheap Chineese makes of drives and high praise for those Gecko products.
I envisoned hardly any TB6600 borad available from China and if possible studied schematics. All of them violate one or several specificartions from datasheet. Hence the density of reported problems.

1. It is very obvious that Toshiba dedicated the Vreg pin for an external capacitor ONLY in order to get the internal 5V supply stable. They tolerate for MO and ALERT pin 30K pullup resistor each. End of story! (based on their data sheet 2014-01-30)
2. Values for absolute maximum ratings are permanently confused with normal operating conditions (even in these forums)
3. Any replication adds annotehr flaw while sometimes (oh!) repair one.
3. Reset left open and not operated while nowbody knows if the internal control machine performs a reset itself.
4. Enable is activate by default after power on .....
5. Driving base of transistor without limiting resistor - apart from torturing the transistor there is no reliable fall back time for TQ
6. ...

Do you believe Gecko drives own any of those silly violations?

I once bought a TB6600 board form Rattm. Now I performed a tear down in order to find out what can be repaired. IN short, I am disappointed (especially because of #1 above).
Of course some makes do well in some few applications. But that is like crossing the road while trafic light is red .....

From all boards I found in internet (being well documeted) one - it is the M166 from SOC robotics (NON CHINESSE OF COURSE!) being mostly well designed. (No, I do not own shares !!) They applied just common sense - no rocket science! Unfortunately they did not include optos for control signals and no dedicated 5V supply for control logic (OK their setup seems to not need it). With these additions it would be a damn robust and good board. There may be others available out there but I found no documentation.
I feel those additons mentioned are essential in order to avoid ground loops and interference between channels - hence provide easy use for anybody. Else a very knowledgeable GND and shield design needs to be established. (see)

My question is: Is there anybody out there who is prepared to generate a reliable PCB and is willing to share it (e.g. at OSHOPARK or elsewhere)? I freely would like to conrtibute to a robust schematic and layout review. Compared to those Chinese replicas the extra components will be below USD 2.0 (voltage regulator, capacitors, logicgates ...). It is unbearable to see so many motivated activists sufferning on Chineese crap (including me :-) )!

BTW: I am a newbie in matters of CNC (grbl running but drivers missing) but have 3 decades of experinece in electronics.
John